1. Field of the Invention
The present invention relates to a photosensitive composition which is useful for fine processing of e.g. lithographic printing plates, printed boards, LSI, TFT liquid crystal display devices, plasma display devices and TAB, and it further relates to an image-forming material, a photosensitive lithographic printing plate and an image-forming method. More particularly, it relates to a negative photosensitive resin composition which is useful for direct image-forming by laser scanning exposure based on digital signals of computers, etc. and which is suitable for exposure with an infrared laser such as a semiconductor laser or a solid state laser.
2. Description of the Background
Lithographic technology employing a photosensitive resin has been widely used for fine processing of printed boards, LSI, TFT liquid crystal display devices, plasma display devices, TAB, etc. for image formation. For such a purpose, it is common to employ a method wherein image exposure is carried out through a mask, and a pattern is formed by utilizing the difference in solubility to a developer between an exposed portion and a non-exposed portion. If a laser beam is employed, a photosensitive resin can be directly scanned for image exposure based on digital information of a computer or the like, whereby not only the productivity but also the resolution, the positional precision, etc., can be improved. Accordingly, a direct image-forming method by a laser is being studied extensively.
As the laser beam, various light sources are known ranging from far ultraviolet rays to microwaves. However, a laser beam useful for lithography from the viewpoint of the laser power, stability, costs, sensitizing ability, etc., is preferably one which emits visible light to infrared light, such as an Ar ion laser, a YAG laser, a helium neon laser or a semiconductor laser. Accordingly, various compositions having photosensitivities within a range of from visible light to infrared light, are being studied.
Among them, a positive photosensitive composition utilizing a phase change of a novolak resin (JP-A-9-43847) is known as a composition which is selectively sensitive to infrared light and has a safe light property against white light, and, as a composition utilizing a thermal reaction by a photo-thermal conversion substance, one utilizing crosslinking of a block isocyanate (JP-A-6-1088, and JP-A-9-43845) or one utilizing a phenolic crosslinking agent (JP-A-8-276558) is known. However, such compositions have had a problem from the viewpoint of the sensitivity and stability.
Further, JP-A-62-143044 and JP-A-62-150242 disclose photosensitive compositions comprising an ethylenic monomer, an organic boron complex and a cation dye. However, the photosensitive compositions disclosed in these publications are sensitive to light in a visible to near infrared region and thus have had a problem in handling under white light.
On the other hand, JP-A-6-175564 discloses a hologram recording material comprising a polymer compound which is a (co)polymer of a vinyl monomer, a compound having at least one ethylenically unsaturated bond, a porphyrazine derivative including a phthalocyanine compound and a sulfonium organic boron complex, and specifically describes an example wherein hologram recording was carried out with a light having a wavelength of from 633 to 647 nm.